Search

The provenancing of Roman natron glass is one of the most challenging problems in the field of archaeometry. Although the use of Sr and Nd isotope ratios and trace element signatures as an indication of provenance has proven promising, there are still many unknowns. In this study, the influence of the different raw materials on the final Sr isotopic composition of Roman natron glass is examined. It is shown that the 87Sr/86Sr ratio in natron glass is significantly influenced by the silicate fraction of the sand used and does not always provide a clear indication of the lime source used. [ABSTRACT FROM AUTHOR]

Because peritoneal metastasis (PM) from ovarian cancer is characterized by non-specific symptoms, it is often diagnosed at advanced stages. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) can be considered a promising drug delivery method for unresectable PM. Currently, the efficacy of intraperitoneal (IP) drug delivery is limited by the off-label use of IV chemotherapeutic solutions, which are rapidly cleared from the IP cavity. Hence, this research aimed to improve PM treatment by evaluating a nanoparticle-loaded, pH-switchable supramolecular polymer hydrogel as a controlled release drug delivery system that can be IP nebulized. Moreover, a multidirectional nozzle was developed to allow nebulization of viscous materials such as hydrogels and to reach an even IP gel deposition. We demonstrated that acidification of the nebulized hydrogelator solution by carbon dioxide, used to inflate the IP cavity during laparoscopic surgery, stimulated the in situ gelation, which prolonged the IP hydrogel retention. In vitro experiments indicated that paclitaxel nanocrystals were gradually released from the hydrogel depot formed, which sustained the cytotoxicity of the formulation for 10 days. Finally, after aerosolization of this material in a xenograft model of PM, tumor progression could successfully be delayed, while the overall survival time was significantly increased compared to non-treated animals.

Longitudinal in vivo monitoring of transplanted cells is crucial to perform cancer research or to assess the treatment outcome of cell-based therapies. While several bio-imaging techniques can be used, magnetic resonance imaging (MRI) clearly stands out in terms of high spatial resolution and excellent soft-tissue contrast. However, MRI suffers from low sensitivity, requiring cells to be labeled with high concentrations of contrast agents. An interesting option is to label cells with clinically approved gadolinium chelates which generate a hyperintense MR signal. However, spontaneous uptake of the label via pinocytosis results in its endosomal sequestration, leading to quenching of the T 1 -weighted relaxation. To avoid this quenching effect, delivery of gadolinium chelates directly into the cytosol via electroporation or hypotonic cell swelling have been proposed. However, these methods are also accompanied by several drawbacks such as a high cytotoxicity, and changes in gene expression and phenotype. Here, we demonstrate that nanoparticle-sensitized laser induced photoporation forms an attractive alternative to efficiently deliver the contrast agent gadobutrol into the cytosol of both HeLa and SK-OV-3 IP1 cells. After intracellular delivery by photoporation the quenching effect is clearly avoided, leading to a strong increase in the hyperintense T 1 -weighted MR signal. Moreover, when compared to nucleofection as a state-of-the-art electroporation platform, photoporation has much less impact on cell viability, which is extremely important for reliable cell tracking studies. Additional experiments confirm that photoporation does not induce any change in the long-term viability or the migratory capacity of the cells. Finally, we show that gadolinium 'labeled' SK-OV-3 IP1 cells can be imaged in vivo by MRI with high soft-tissue contrast and spatial resolution, revealing indications of potential tumor invasion or angiogenesis.

Intra-abdominal dissemination of peritoneal nodules, a condition known as peritoneal carcinomatosis (PC), is typically diagnosed in ovarian cancer patients at the advanced stages. The current treatment of PC consists of perioperative systemic chemotherapy and cytoreductive surgery, followed by intra-abdominal flushing with solutions of chemotherapeutics such as cisplatin and oxaliplatin. In this study, we developed cisplatin-loaded polyarginine-hyaluronic acid nanoscale particles (Cis-pARG-HA NPs) with high colloidal stability, marked drug loading efficiency, unimpaired biological activity, and tumor-targeting ability. Injected Cis-pARG-HA NPs showed enhanced antitumor activity in a rat model of PC, compared to injection of the free cisplatin drug. The activity of Cis-pARG-HA NPs could even be further improved when administered by an intra-abdominal aerosol therapy, referred to as pressurized intraperitoneal aerosol chemotherapy (PIPAC). PIPAC is hypothesized to ensure a more homogeneous drug distribution together with a deeper drug penetration into peritoneal tumor nodules within the abdominal cavity. Using fluorescent pARG-HA NPs, this enhanced nanoparticle deposit on tumors could indeed be observed in regions opposite the aerosolization nozzle. Therefore, this study demonstrates that nanoparticles carrying chemotherapeutics can be synergistically combined with the PIPAC technique for IP therapy of disseminated advanced ovarian tumors, while this synergistic effect was not observed for the administration of free cisplatin.

Mineralization of hydrogel biomaterials with calcium phosphate (CaP) is considered advantageous for bone regeneration. Mineralization can be both induced by the enzyme alkaline phosphatase (ALP) and promoted by calcium-binding biomolecules, such as plant-derived polyphenols. In this study, ALP-loaded gellan gum (GG) hydrogels were enriched with gallotannins, a subclass of polyphenols. Five preparations were compared, namely three tannic acids of differing molecular weight (MW), pentagalloyl glucose (PGG), and a gallotannin-rich extract from mango kernel ( Mangifera indica L.). Certain gallotannin preparations promoted mineralization to a greater degree than others. The various gallotannin preparations bound differently to ALP and influenced the size of aggregates of ALP, which may be related to ability to promote mineralization. Human osteoblast-like Saos-2 cells grew in eluate from mineralized hydrogels. Gallotannin incorporation impeded cell growth on hydrogels and did not impart antibacterial activity. In conclusion, gallotannin incorporation aided mineralization but reduced cytocompatibility.

Metal-on-metal (MoM) prostheses, in which the bearing surfaces are made of a metal alloy, may release metal ions upon wear and corrosion, potentially inducing both local and systemic toxicity. As the systemic cobalt concentration increases with the degree of implant wear, this concentration needs to be monitored as a means of assessing implant function and the risk of adverse effects. Here, we report on the development, validation and application of a method to quantitatively assess these Co concentrations in whole blood, based on the combination of volumetric absorptive microsampling (VAMS) and inductively coupled plasma - mass spectrometry (ICP-MS). This method could allow patients to collect the required samples at home, as VAMS samples are easy to collect and can be transported to the laboratory via regular mail. The extraction procedure utilized an alkaline extraction mixture with yttrium as internal standard and proved to be independent of the hematocrit and age of the VAMS samples. The Co concentrations in the VAMS extracts were measured using quadrupole-based ICP-MS. The analytical method covers a range of 2-300 μg/L and displays excellent accuracy (bias ≤4%) and imprecision (relative standard deviation ≤ 5% and ≤15% at the lower limit of quantitation (LLOQ)). The method was applied to venous VAMS samples of MoM prosthesis patients (n = 78), yielding promising results. The comparison of these results with those obtained on the corresponding liquid whole blood samples, showed a correlation coefficient of 0.99 and 87% of the data fulfilled the criteria proposed by the Royal College of Pathologists of Australasia (RCPA)., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The present work focuses on the development of novel injectable, self-gelling composite hydrogels based on two types of low esterified amidated pectins from citrus peels and apple pomace. Sol-gel-derived, calcium-rich bioactive glass (BG) fillers in a particle form are applied as delivery vehicles for the release of Ca 2+ ions to induce internal gelation of pectins. Composites were prepared by a relatively simple mixing technique, using 20% w/v BG particles of two different sizes (2.5 and <45 μm). Smaller particles accelerated pectin gelation slightly faster than bigger ones, which appears to result from the higher rate of Ca 2+ ion release. μCT showed inhomogeneous distribution of the BG particles within the hydrogels. All composite hydrogels exhibited strong antibacterial activity against methicilin-resistant Staphylococcus aureus. The mineralization process of pectin-BG composite hydrogels occurred upon incubation in simulated body fluid for 28 days. In vitro studies demonstrated cytocompatibility of composite hydrogels with MC3T3-E1 osteoblastic cells., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Mineralization of hydrogels is desirable prior to applications in bone regeneration. CaCO 3 is a widely used bone regeneration material, and Mg, when used as a component of calcium phosphate biomaterials, has promoted bone-forming cell adhesion and proliferation and bone regeneration. In this study, gellan gum hydrogels were mineralized with carbonates containing different amounts of calcium (Ca) and magnesium (Mg) by alternate soaking in, firstly, a calcium and/or magnesium ion solution and, secondly, a carbonate ion solution. This alternate soaking cycle was repeated five times. Five different calcium and/or magnesium ion solutions, containing different molar ratios of Ca to Mg ranging from Mg free to Ca free were compared. Carbonate mineral formed in all sample groups subjected to the alternate soaking cycle. Ca : Mg elemental ratio in the mineral formed was higher than in the respective mineralizing solution. Mineral formed in the absence of Mg was predominantly CaCO 3 in the form of a mixture of calcite and vaterite. Increasing the Mg content in the mineral formed led to the formation of magnesian calcite and decreased the total amount of the mineral formed and its crystallinity. Hydrogel mineralization and increasing Mg content in mineral formed did not obviously improve proliferation of MC3T3-E1 osteoblast-like cells or differentiation after 7 days., (© 2018 John Wiley & Sons, Ltd.)

Inductively coupled plasma mass spectrometry (ICP-MS) was combined with UV-vis absorption spectroscopy and transmission electron microscopy to determine the size, composition, and intrinsic absorption coefficient μ i of 4 to 11 nm sized colloidal CsPbBr 3 nanocrystals (NCs). The ICP-MS measurements demonstrate the nonstoichiometric nature of the NCs, with a systematic excess of lead for all samples studied. Rutherford backscattering measurements indicate that this enrichment in lead concurs with a relative increase in the bromide content. At high photon energies, μ i is independent of the nanocrystal size. This allows the nanocrystal concentration in CsPbBr 3 nanocolloids to be readily obtained by a combination of absorption spectroscopy and the CsPbBr 3 sizing curve.

Mineralization of hydrogel biomaterials is desirable to improve their suitability as materials for bone regeneration. In this study, gellan gum (GG) hydrogels were formed by simple mixing of GG solution with bioactive glass microparticles of 45S5 composition, leading to hydrogel formation by ion release from the amorphous bioactive glass microparticles. This resulted in novel injectable, self-gelling composites of GG hydrogels containing 20% bioactive glass. Gelation occurred within 20 min. Composites containing the standard 45S5 bioactive glass preparation were markedly less stiff. X-ray microcomputed tomography proved to be a highly sensitive technique capable of detecting microparticles of diameter approximately 8 μm, that is, individual microparticles, and accurately visualizing the size distribution of bioactive glass microparticles and their aggregates, and their distribution in GG hydrogels. The widely used melt-derived 45S5 preparation served as a standard and was compared with a calcium-rich, sol-gel derived preparation (A2), as well as A2 enriched with zinc (A2Zn5) and strontium (A2Sr5). A2, A2Zn, and A2Sr bioactive glass particles were more homogeneously dispersed in GG hydrogels than 45S5. Composites containing all four bioactive glass preparations exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus. Composites containing A2Zn5 and A2Sr5 bioactive glasses supported the adhesion and growth of osteoblast-like cells and were considerably more cytocompatible than 45S5. All composites underwent mineralization with calcium-deficient hydroxyapatite upon incubation in simulated body fluid. The extent of mineralization appeared to be greatest for composites containing A2Zn5 and 45S5. The results underline the importance of the choice of bioactive glass when preparing injectable, self-gelling composites., (Copyright © 2018 John Wiley & Sons, Ltd.)

A systematic evaluation of four different ICP sample introduction systems to be used in the context of metabolite profiling of chlorine-containing pharmaceuticals via HPLC-ICP-MS was carried out using diclofenac and its major metabolite, 4'-hydroxy-diclofenac, as model compounds. The strict requirements for GMP validation of chromatographic methods in the pharmaceutical industry were adhered to in this context. The final aim of this investigation is an extension of the applicability and validatability of HPLC-ICP-MS in the field of pharmaceutical R&D. Five different gradient programmes were tested while the baseline peak width (w b ), peak capacity (P), USP tailing factor (A s ) and USP signal-to-noise ratio (USP S/N) were determined as major indicators of the chromatographic performance and the values obtained were compared to the corresponding FDA recommendations (if applicable). Four different ICP-MS sample introductions systems were investigated involving two units typically working at higher flow rates (∼1.0 mL min -1 ) and another two systems working at lower flow rates (∼0.1 mL min -1 ). Optimal conditions with potential for applicability under GMP conditions were found at a mobile phase flow rate of 1.0 mL min -1 by using a pneumatic micro-flow LC nebulizer mounted onto a Peltier-cooled cyclonic spray chamber cooled to -1 °C for sample introduction. Under these conditions, HPLC-ICP-MS provided a chromatographic performance similar to that of HPLC with UV detection. The peak shape (USP tailing factor = 1.1-1.4) was significantly improved compared to that obtained with the Peltier-cooled Scott-type spray chamber. Two alternative sample introduction systems - a POINT ® and a High-Temperature Torch-Integrated Sample Introduction System (hTISIS) - were also tested at a flow rate of 0.1 mL min -1 using a chromatographic column with 1.0 mm ID. Although these systems allowed the peak shape to be improved compared to that obtained with the traditional Scott-type spray chamber, the limits of detection and of quantification achievable were strongly compromised due to the significantly lower sensitivity observed for Cl. In addition to a comparison of the aforementioned sample introduction systems, also the effect of spray chamber temperature was evaluated and it was demonstrated that proper temperature control plays an essential role in the optimization of HPLC-ICP-MS methods., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Mineralized hydrogels are increasingly gaining attention as biomaterials for bone regeneration. The most common mineralization strategy has been addition of preformed inorganic particles during hydrogel formation. This maintains injectability. One common form of bone cement is formed by mixing particles of the highly reactive calcium phosphate alpha-tricalcium phosphate (α-TCP) with water to form hydroxyapatite (HA). The calcium ions released during this reaction can be exploited to crosslink anionic, calcium-binding polymers such as the polysaccharide gellan gum (GG) to induce hydrogel formation. In this study, three different amounts of α-TCP particles were added to GG polymer solution to generate novel, injectable hydrogel-inorganic composites. Distribution of the inorganic phase in the hydrogel was studied by high resolution microcomputer tomography (µCT). Gelation occurred within 30 min. α-TCP converted to HA. µCT revealed inhomogeneous distribution of the inorganic phase in the composites. These results demonstrate the potential of the composites as alternatives to traditional α-TCP bone cement and pave the way for incorporation of biologically active substances and in vitro and in vivo testing. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 822-828, 2018., (© 2017 Wiley Periodicals, Inc.)

A novel quantification approach, compensating for the effect of gradient elution on the instrumental response during reversed phase high-performance liquid chromatography - inductively coupled plasma - tandem mass spectrometry analysis, has been developed and validated. As a proof of concept, diclofenac and its related compounds, including its major metabolite i.e. 4'-hydroxy-diclofenac, have been quantitatively determined in human plasma matrix. An inductively coupled plasma - tandem mass spectrometer has been applied for the interference-free determination of Cl as 35 ClH 2 + using H 2 as a reaction gas in the collision/reaction cell. The effect of the eluent composition on the instrumental response for Cl has been thoroughly investigated for the most common organic solvents in reversed phase high-performance liquid chromatography, i.e. methanol and acetonitrile. A proper mathematical function describing the effect of the eluent composition on the sensitivity for Cl, monitored as 35 , permitted adequate correction for the otherwise detrimental effect of gradient elution for both solvents. Validation using synthetically degraded diclofenac samples spiked with its major metabolite, 4'-hydroxy-diclofenac, demonstrated appropriate accuracy (recovery for 4'-hydroxy-diclofenac between 95 and 105%) and >90% and >80% recovery for Cl using acetonitrile and methanol, respectively. When applied to spiked human plasma samples (the most important matrix in drug metabolism studies), a satisfactory accuracy (recovery of 92-98%) and precision (<4% RSD) were established for both 4'-hydroxy-diclofenac and diclofenac. The limit of quantification for Cl (as diclofenac) using the novel method was 0.05 mg L 2 . This value can be significantly improved (to 0.002 mg L + , permitted adequate correction for the otherwise detrimental effect of gradient elution for both solvents. Validation using synthetically degraded diclofenac samples spiked with its major metabolite, 4'-hydroxy-diclofenac, demonstrated appropriate accuracy (recovery for 4'-hydroxy-diclofenac between 95 and 105%) and >90% and >80% recovery for Cl using acetonitrile and methanol, respectively. When applied to spiked human plasma samples (the most important matrix in drug metabolism studies), a satisfactory accuracy (recovery of 92-98%) and precision (<4% RSD) were established for both 4'-hydroxy-diclofenac and diclofenac. The limit of quantification for Cl (as diclofenac) using the novel method was 0.05 mg L -1 . This value can be significantly improved (to 0.002 mg L -1 ) via on-line sample pre-concentration using a trapping chromatographic column and a time-programmable 10 ports/2 positions micro valve., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Gellan gum hydrogels functionalized with alkaline phosphatase were enzymatically mineralized with phosphates in mineralization medium containing calcium (Ca) and zinc (Zn) to improve their suitability as biomaterials for bone regeneration. The aims of the study were to endow mineralized hydrogels with antibacterial activity by incorporation of Zn in the inorganic phase, and to investigate the effect of Zn incorporation on the amount and type of mineral formed, the compressive modulus of the mineralized hydrogels and on their ability to support adhesion and growth of MC3T3-E1 osteoblast-like cells. Mineralization medium contained glycerophosphate (0.05 m) and three different molar Ca:Zn ratios, 0.05:0, 0.04:0.01 and 0.025:0.025 (all mol/dm 3 ), hereafter referred to as A, B and C, respectively. FTIR, SAED and TEM analysis revealed that incubation for 14 days caused the formation of predominantly amorphous mineral phases in sample groups A, B and C. The presence of Zn in sample groups B and C was associated with a drop in the amount of mineral formed and a smaller mineral deposit morphology, as observed by SEM. ICP-OES revealed that Zn was preferentially incorporated into mineral compared to Ca. Mechanical testing revealed a decrease in compressive modulus in sample group C. Sample groups B and C, but not A, showed antibacterial activity against biofilm-forming, methicillin-resistant Staphylococcus aureus. All sample groups supported cell growth. Zn incorporation increased the viable cell number. The highest values were seen on sample group C. In conclusion, the sample group containing the most Zn, i.e. group C, appears to be the most promising. Copyright © 2015 John Wiley & Sons, Ltd., (Copyright © 2015 John Wiley & Sons, Ltd.)

Quantitative determination of the candidate drug molecule and its metabolites in biofluids and tissues is an inevitable step in the development of new pharmaceuticals. Because of the time-consuming and expensive nature of the current standard technique for quantitative metabolite profiling, i.e., radiolabeling followed by high-performance liquid chromatography (HPLC) with radiodetection, the development of alternative methodologies is of great interest. In this work, a simple, fast, sensitive, and accurate method for the quantitative metabolite profiling of an amino group containing drug (levothyroxine) and its metabolites in human plasma, based on precolumn derivatization followed by HPLC-inductively coupled plasma mass spectrometry (ICPMS), was developed and validated. To introduce a suitable "heteroelement" (defined here as an element that is detectable with ICPMS), an inexpensive and commercially available reagent, tetrabromophthalic anhydride (TBPA) was used for the derivatization of free NH 2 -groups. The presence of a known number of I atoms in both the drug molecule and its metabolites enabled a cross-validation of the newly developed derivatization procedure and quantification based on monitoring of the introduced Br. The formation of the derivatives was quantitative, providing a 4:1 stoichiometric Br/NH 2 ratio. The derivatives were separated via reversed-phase HPLC with gradient elution. Bromine was determined via ICPMS at a mass-to-charge ratio of 79 using H 2 as a reaction gas to ensure interference-free detection, and iodine was determined at a mass-to-charge ratio of 127 for cross-validation purposes. The method developed shows a fit-for-purpose accuracy (recovery between 85% and 115%) and precision (repeatability <15% RSD). The limit of quantification (LoQ) for Br was approximately 100 μg/L.

The suitability of hydrogel biomaterials for bone regeneration can be improved by incorporation of an inorganic phase in particle form, thus maintaining hydrogel injectability. In this study, carbonate microparticles containing different amounts of calcium (Ca) and magnesium (Mg) were added to solutions of the anionic polysaccharide gellan gum (GG) to crosslink GG by release of Ca 2+ and Mg 2+ from microparticles and thereby induce formation of hydrogel-microparticle composites. It was hypothesized that increasing Mg content of microparticles would promote GG hydrogel formation. The effect of Mg incorporation on cytocompatibility and cell growth was also studied. Microparticles were formed by mixing Ca 2+ and Mg 2+ and [Formula: see text] ions in varying concentrations. Microparticles were characterized physiochemically and subsequently mixed with GG solution to form hydrogel-microparticle composites. The elemental Ca:Mg ratio in the mineral formed was similar to the Ca:Mg ratio of the ions added. In the absence of Mg, vaterite was formed. At low Mg content, magnesian calcite was formed. Increasing the Mg content further caused formation of amorphous mineral. Microparticles of vaterite and magnesium calcite did not induce GG hydrogel formation, but addition of Mg-richer amorphous microparticles induced gelation within 20 min. Microparticles were dispersed homogeneously in hydrogels. MG-63 osteoblast-like cells were cultured in eluate from hydrogel-microparticle composites and on the composites themselves. All composites were cytocompatible. Cell growth was highest on composites containing particles with an equimolar Ca:Mg ratio. In summary, carbonate microparticles containing a sufficient amount of Mg induced GG hydrogel formation, resulting in injectable, cytocompatible hydrogel-microparticle composites.

Mineralization of hydrogels, desirable for bone regeneration applications, may be achieved enzymatically by incorporation of alkaline phosphatase (ALP). ALP-loaded gellan gum (GG) hydrogels were mineralized by incubation in mineralization media containing calcium and/or magnesium glycerophosphate (CaGP, MgGP). Mineralization media with CaGP:MgGP concentrations 0.1:0, 0.075:0.025, 0.05:0.05, 0.025:0.075 and 0:0.1 (all values mol/dm 3 , denoted A, B, C, D and E, respectively) were compared. Mineral formation was confirmed by IR and Raman, SEM, ICP-OES, XRD, TEM, SAED, TGA and increases in the the mass fraction of the hydrogel not consisting of water. Ca was incorporated into mineral to a greater extent than Mg in samples mineralized in media A-D. Mg content and amorphicity of mineral formed increased in the order A < B < C < D. Mineral formed in media A and B was calcium-deficient hydroxyapatite (CDHA). Mineral formed in medium C was a combination of CDHA and an amorphous phase. Mineral formed in medium D was an amorphous phase. Mineral formed in medium E was a combination of crystalline and amorphous MgP. Young's moduli and storage moduli decreased in dependence of mineralization medium in the order A > B > C > D, but were significantly higher for samples mineralized in medium E. The attachment and vitality of osteoblastic MC3T3-E1 cells were higher on samples mineralized in media B-E (containing Mg) than in those mineralized in medium A (not containing Mg). All samples underwent degradation and supported the adhesion of RAW 264.7 monocytic cells, and samples mineralized in media A and B supported osteoclast-like cell formation. Copyright © 2014 John Wiley & Sons, Ltd., (Copyright © 2014 John Wiley & Sons, Ltd.)

This paper reports on an evaluation of the suitability of a novel sample collection approach, volumetric absorptive micro-sampling (VAMS), in the context of the determination of ultra-trace concentrations of prosthesis-related metals (Al, Ti, V, Co, Cr, Ni, Sr and Zr) in whole blood. In a first phase, a simple dilute-and-shoot approach (100-fold dilution) followed by tandem ICP - mass spectrometry (ICP-MS/MS) analysis was developed for the accurate and sensitive determination of the target elements. The ICP-MS/MS method relies on the use of mass shift reactions proceeding when pressurizing the collision/reaction cell (CRC) with CH 3 F/He for dealing with spectral overlap. Limits of detection (LoDs) between 0.3 and 30 ng L -1 were attained in a multi-element approach. The accuracy of the method was demonstrated via successful analysis of the reference materials Seronorm Whole Blood Levels 1 and 3, and real venous blood samples, spiked with the target elements at different concentration levels (5-50 μg L -1 ). Although the implementation of VAMS devices introduced contamination problems for Al, Cr and Ni, VAMS followed by ICP-MS/MS analysis shows potential for future real-life routine applications when assessing levels of Ti, V, Co, Sr and/or Zr., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Hydrogels offer several advantages as biomaterials for bone regeneration, including ease of incorporation of soluble substances such as mineralization-promoting enzymes and antibacterial agents. Mineralization with calcium phosphate (CaP) increases bioactivity, while antibacterial activity reduces the risk of infection. Here, gellan gum (GG) hydrogels were enriched with alkaline phosphatase (ALP) and/or Seanol(®), a seaweed extract rich in phlorotannins (brown algae-derived polyphenols), to induce mineralization with CaP and increase antibacterial activity, respectively. The sample groups were unmineralized hydrogels, denoted as GG, GG/ALP, GG/Seanol and GG/Seanol/ALP, and hydrogels incubated in mineralization medium (0.1 M calcium glycerophosphate), denoted as GG/ALP&#95;min, GG/Seanol&#95;min and GG/Seanol/ALP&#95;min. Seanol(®) enhanced mineralization with CaP and also increased compressive modulus. Seanol(®) and ALP interacted in a non-covalent manner. Release of Seanol(®) occurred in a burst phase and was impeded by ALP-mediated mineralization. Groups GG/Seanol and GG/ALP/Seanol exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus. GG/Seanol/ALP&#95;min, but not GG/Seanol&#95;min, retained some antibacterial activity. Eluates taken from groups GG/ALP&#95;min, GG/Seanol&#95;min and GG/ALP/Seanol&#95;min displayed comparable cytotoxicity towards MG-63 osteoblast-like cells. These results suggest that enrichment of hydrogel biomaterials with phlorotannin-rich extracts is a promising strategy to increase mineralizability and antibacterial activity.

A fast, accurate and precise method for the separation and determination of the total contents of drug-related Cl and Br in human blood plasma, based on high performance liquid chromatography - inductively coupled plasma - tandem mass spectrometry (HPLC-ICP-MS/MS), has been developed. The novel approach was proved to be a suitable alternative to the presently used standard methodology (i.e. based on a radiolabelled version of the drug molecule and radiodetection), while eliminating the disadvantages of the latter. Interference-free determination of (35)Cl has been accomplished via ICP-MS/MS using H2 as reaction gas and monitoring the (35)ClH2(+) reaction product at mass-to-charge ratio of 37. Br could be measured "on mass" at a mass-to-charge of 79. HPLC was relied on for the separation of the drug-related entities from the substantial amount of inorganic Cl. The method developed was found to be sufficiently precise (repeatability <10% RSD) and accurate (recovery between 95 and 105%) and shows a linear dynamic range (R(2)>0.990) from the limit of quantification (0.05 and 0.01 mg/L for Cl and Br in blood plasma, respectively) to at least 5 and 1mg/L for Cl and Br, respectively. Quantification via either external or internal standard calibration provides reliable results for both elements. As a proof-of-concept, human blood plasma samples from a clinical study involving a newly developed Cl- and Br-containing active pharmaceutical ingredient were analysed and the total drug exposure was successfully described. Cross-validation was achieved by comparing the results obtained on Cl- and on Br-basis., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This paper is intended as a tutorial review on the use of inductively coupled plasma - tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H2, O2 and NH3, also the use of promising alternative gases, such as CH3F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Interference-free conditions, allowing straightforward As and Se determination, can be obtained by using CH3F (a mixture of 10% CH3F and 90% He) as a reaction gas in tandem ICP-mass spectrometry (ICP-MS/MS). Both target elements react via CH3F addition and subsequent HF elimination, rendering AsCH2 (+) and SeCH2 (+) the respective favored reaction product ions. Instrumental limits of detection were 0.2 ng L(-1) for As and below 10 ng L(-1) for Se, using either (77)Se, (78)Se, or (80)Se. Neither addition of carbon to the solutions, nor admixing of additional He into the octopole reaction cell resulted in a further improvement of the LoDs, despite the increase in analyte signal intensity. By using synthetic matrices, containing elements giving rise to ions interfering at either the original mass-to-charge ratios or those of the reaction products, absence of spectral overlap could be demonstrated. This conclusion was corroborated by successful As and Se determination in a collection of reference materials from plant, animal, or environmental origin, displaying a considerable range of As and Se contents. These accurate results were obtained via external calibration using Te as an internal standard. The high efficiency reaction between As and CH3F and the possibility to use the major isotope of Se provides enhanced detection power versus other techniques, such as sector-field ICP-mass spectrometry, while the possibility to monitor at least three Se isotopes interference-free also enables isotopic analysis.

Various types of nanofibers are increasingly used in tissue engineering, mainly for their ability to mimic the architecture of tissue at the nanoscale. We evaluated the adhesion, growth, viability, and differentiation of human osteoblast-like MG 63 cells on polylactide (PLA) nanofibers prepared by needle-less electrospinning and loaded with 5 or 15 wt % of hydroxyapatite (HA) nanoparticles. On day 7 after seeding, the cell number was the highest on samples with 15 wt % of HA. This result was confirmed by the XTT test, especially after dynamic cultivation, when the number of metabolically active cells on these samples was even higher than on control polystyrene. Staining with a live/dead kit showed that the viability of cells on all nanofibrous scaffolds was very high and comparable to that on control polystyrene dishes. An enzyme-linked immunosorbent assay revealed that the concentration of osteocalcin was also higher in cells on samples with 15 wt % of HA. There was no immune activation of cells (measured by production of TNF-alpha), associated with the incorporation of HA. Moreover, the addition of HA suppressed the creep behavior of the scaffolds in their dry state. Thus, nanofibrous PLA scaffolds have potential for bone tissue engineering, particularly those with 15 wt % of HA., (© 2013 Wiley Periodicals, Inc.)

Interest is growing in the use of hydrogels as bone tissue-engineering (TE) scaffolds due to advantages such as injectability and ease of incorporation of active substances such as enzymes. Hydrogels consisting of gellan gum (GG), an inexpensive calcium-crosslinkable polysaccharide, have been applied in cartilage TE. To improve GG suitability as a material for bone TE, alkaline phosphatase (ALP), an enzyme involved in mineralization of bone by cleaving phosphate from organic phosphate, was incorporated into GG hydrogels to induce mineralization with calcium phosphate (CaP). Incorporated ALP induced formation of apatite-like material on the submicron scale within GG gels, as shown by FTIR, SEM, EDS, XRD, ICP-OES, TGA and von Kossa staining. Increasing ALP concentration increased amounts of CaP as well as stiffness. Mineralized GG was able to withstand sterilization by autoclaving, although stiffness decreased. In addition, mineralizability and stiffness of GG was enhanced by the incorporation of polydopamine (PDA). Furthermore, mineralization of GG led to enhanced attachment and vitality of cells in vitro while cytocompatibility of the mineralized gels was comparable to one of the most commonly used bone substitute materials. The results proved that ALP-mediated enzymatic mineralization of GG could be enhanced by functionalization with PDA., (Copyright © 2012 John Wiley & Sons, Ltd.)

Methyl fluoride (a mixture of 10% CH3F and 90% of He) was evaluated as a reaction gas in inductively coupled plasma-tandem mass spectrometry (ICPMS/MS) in the context of the determination of ultratrace concentrations of medically relevant metals (Al, Co, Cr, Mn, Ni, Ti, and V) in blood serum and urine. Via product ion scanning, whereby only ions of the mass-to-charge ratio of the target nuclide were admitted into the octopole reaction cell, the various reaction product ions formed for each of the target elements were identified at different CH3F gas flow rates. Limits of detection (LODs) and of quantification (LOQs) and linearity of the calibration curve were documented under (i) optimized ICPMS/MS conditions for single-element monitoring and (ii) compromise conditions, allowing for multielement determination. Even under compromise settings, instrumental LODs were below 10 ng/L for all target elements, while the use of CH3F provided interference-free conditions for their determination in the biofluids of interest. Quantitative data obtained for Seronorm blood serum and urine reference materials were in excellent agreement with the corresponding reference values and/or results obtained using double-focusing sector-field ICPMS (for those elements for which no certified values were available or that were affected during reconstitution), proving the potential of this reaction gas for multielement ultratrace analysis via ICPMS/MS.

Hydrogels of biocompatible calcium-crosslinkable polysaccharide gellan gum (GG) were enriched with bioglass particles to enhance (i) mineralization with calcium phosphate (CaP); (ii) antibacterial properties and (iii) growth of bone-forming cells for future bone regeneration applications. Three bioglasses were compared, namely one calcium-rich and one calcium-poor preparation both produced by a sol-gel technique (hereafter referred to as A2 and S2, respectively) and one preparation of composition close to that of the commonly used 45S5 type (hereafter referred to as NBG). Incubation in SBF for 7 d, 14 d and 21 d caused apatite formation in bioglass-containing but not in bioglass-free samples, as confirmed by FTIR, XRD, SEM, ICP-OES, and measurements of dry mass, i.e. mass attributable to polymer and mineral and not water. Mechanical testing revealed an increase in compressive modulus in samples containing S2 and NBG but not A2. Antibacterial testing using biofilm-forming meticillin-resistant staphylococcus aureus (MRSA) showed markedly higher antibacterial activity of samples containing A2 and S2 than samples containing NBG and bioglass-free samples. Cell biological characterization using rat mesenchymal stem cells (rMSCs) revealed a stimulatory effect of NBG on rMSC differentiation. The addition of bioglass thus promotes GG mineralizability and, depending on bioglass type, antibacterial properties and rMSC differentiation.

Ti is frequently used in implants and prostheses and it has been shown before that the presence of these in the human body can lead to elevated Ti concentrations in body fluids such as serum and urine. As identification of the exact mechanisms responsible for this increase in Ti concentrations, and the risks associated with it, are not fully understood, it is important to have sound analytical methods that enable straightforward quantification of Ti levels in body fluids (for both implanted and non-implanted individuals). Until now, only double-focusing sector field ICP-mass spectrometry (SF-ICP-MS) offered limits of detection that are good enough to deal with the very low basal levels of Ti in human serum. This work reports on the development of a novel method for the accurate and precise determination of trace levels of Ti in human serum samples, based on the use of ICP-MS/MS. O2 and NH3/He have been compared as reaction gases. While the use of O2 did not enable to overcome all spectral interferences, it has been shown that conversion of Ti(+) ions into Ti(NH3)6(+) cluster ions by using NH3/He as a reaction gas in an ICP-QQQ-MS system, operated in MS/MS mode, provided interference-free conditions and sufficiently low limits of detection, down to 3 ng L(-1) (instrumental detection limit obtained for the most abundant Ti isotope). The accuracy of the method proposed was evaluated by analysis of a Seronorm Trace Elements Serum L-1 reference material and by comparing the results obtained with those achieved by means of SF-ICP-MS. As a proof-of-concept, the newly developed method was successfully applied to the determination of Ti in serum samples obtained from individuals with and without Ti-based implants. All results were found to be in good agreement with those obtained by means of SF-ICP-MS. The typical basal Ti level in human serum was found to be <1 μg L(-1), while values in the range of 2-6 μg L(-1) were observed for implanted patients., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Membranes of the autologous blood-derived biomaterial platelet-rich fibrin (PRF) were mineralized enzymatically with calcium phosphate (CaP) by the incorporation of alkaline phosphatase (ALP) followed by incubation for 3 days in solutions of either 0.1 M calcium glycerophosphate (CaGP) or a combination of CaGP and magnesium glycerophosphate (CaGP:MgGP; both 0.05 M), resulting in the formation of two different PRF-mineral composites. Fourier transform infrared spectroscopy, transmission electron microscopy and selected area electron diffraction examinations showed that the CaP formed was amorphous. Inductively coupled plasma optical emission spectroscopy analysis revealed similar amounts of Ca and P in both composite types, while a smaller amount of Mg (Ca:Mg molar ratio = 10) was detected in the composites formed in the CaGP:MgGP solution, which was supported by the results of energy-dispersive x-ray spectroscopy-based elemental mapping. Scanning electron microscopy (SEM) imaging showed that the mineral deposits in PRF incubated in the CaGP:MgGP solution were markedly smaller. The mass percentage attributable to the mineral phase was similar in both composite types. MTT and WST tests with SAOS-2 cells revealed that incubation in the CaGP:MgGP solution had no negative effect on cytocompatibility and cell proliferation compared to the CaGP solution. Cells on all samples displayed a well-spread morphology as revealed by SEM imaging. In conclusion, the incorporation of Mg reduces mineral deposit dimensions and promotes cell proliferation.